This invention relates in general to wheel chuck assemblies.
Light weight alloy vehicle wheels are becoming increasingly popular. Such wheels typically include an annular wheel rim that carries a tire. A circular wheel disc is formed across one end of the wheel rim. The wheel disc usually includes a central hub portion supported within the wheel rim by a plurality of wheel spokes. A central pilot hole and plurality of wheel mounting holes are formed through the wheel hub.
One conventional process for manufacturing light weight alloy wheels involves pouring molten metal into a wheel mold to form a casting of a one-piece wheel. After the molten metal solidifies, the wheel casting is removed from the mold. The wheel casting is oversized and is machined to a final shape. Alternately, a full face wheel disc that includes the outboard tire bead retaining flange is cast from a light weight alloy and machined to final shape. A partial wheel rim that can be rolled from a strip of steel is then welded to an inboard surface of the wheel disc to form a two piece wheel. Such a wheel combines the low cost and strength of a steel rim with a pleasing aesthetic appearance of a wheel disc cast from a light weight metal and is usually referred to as a bimetal wheel.
Machining the wheel or wheel disc casting typically includes multiple operations. Sawing machines cut any casting gates and risers from the casting. A drilling machine is used to drill the wheel mounting holes through the wheel hub. The wheel casting is then mounted upon a wheel lathe for machining to its final shape. During the lathe operations, the inside surface of the wheel hub is usually faced to provide a flat mounting surface. Similarly, the outboard wheel hub surface is faced and both the inside and outside of the wheel rim are turned to their final shapes. The central pilot hole is usually drilled while the casting is clamped in the lathe for turning the inboard tire bead seat.
Referring now to the drawings, there is shown generally at 10 in FIGS. 1 and 2 a prior art wheel chuck. The known chuck 10 is suitable for clamping a wheel casting (not shown) or vehicle wheel 12 (as shown in FIG. 2) upon a wheel lathe (not shown). The chuck 10 includes a plurality of jaws 14. While three jaws 14 are shown in FIG. 1, the chuck 10 also may have any suitable number of jaws. As best seen in FIG. 2, each jaw 14 includes a stepped portion 16 that includes a plurality of arcuate shaped clamping surfaces labeled 18, 20, and 22, having different radii. The stepped portion 16 is carried upon the upper surface of a wedge shaped actuator plate 24 and is attached thereto by threaded fasteners 28. Alternatively, the stepped portion 16 and the respective actuator plate 24 may be formed integrally as a one-piece jaw (not shown). A guide rib 26 extends from the lower surface of each actuator plate 24 in a radial direction from the center of the chuck 10. The guide rib 26 is typically formed having an inverted T cross sectional shape.
The actuator plates 24 are moveably mounted upon a support structure, indicated generally at 30 in FIG. 2. The support structure 30 includes a circular support plate 31 that is rotatably supported by bearings 34 upon a cylindrical riser 36. The support plate 31 has a first face 32 and a second face 33 that faces the riser 36. A plurality of radial slots 38 having an inverted T cross sectional shape are formed in the first face 32 of the support plate 31 A guide rib 26 having a cross sectional shape that mirrors the support plate radial slots 38 is formed on the surface of each actuator plate that is adjacent to the support plate 31. Each of the support plate radial slots 38 slidably receives a corresponding actuator plate guide rib 26 and cooperates with the rib to retain the actuator plate 24 upon the support plate 31 while guiding the actuator plate for movement in a radial direction. The face place 32 is drivingly coupled to a rotatable lathe spindle 40 that passes through a central riser aperture 42 formed through a riser back plate 43.
Prior to mounting of the vehicle wheel 12 upon the chuck 10 for machining operations, at least one of the jaws 14 is moved in an outward radial direction, as generally indicated by the arrow labeled 44 in FIG. 2, to an open position. The movement is accomplished by urging the corresponding guide rib 26 outward within its respective face plate slot 38 by a conventional hydraulic ram or a mechanical mechanism (not shown). Typically, all of the jaws 14 are simultaneously moved outward. Once the jaws 14 are opened, the wheel 12 is placed upon an appropriate step, such as step 20. The chuck 10 can accommodate wheels of different diameters (not shown) that would be placed upon steps 18 and 22, respectively. The jaws 14 are then moved in a radial inward direction to a closed position, as indicated by the arrow labeled 44A, clamping the wheel 12 within the chuck 10.
The jaws 14, the actuator plates 24, and the conventional hydraulic ram or the mechanical mechanism operate as a clamping mechanism for the chuck 10. However, other chuck clamping mechanisms are generally known, such as an arrangement of a yoke plate, guide pins, and locking arm.
During machining of the vehicle wheel 12, the lathe spindle 40 rotates the chuck 10 and the wheel 12, as indicated in FIG. 1 by an arrow labeled 46, while a tool (not shown) is pressed against a surface of the wheel. The tool cuts into the wheel surface to remove small pieces, or chips, of metal. Because or the rotation of the wheel 12 and the wheel chuck 10, the metal chips cut from the wheel 12 are thrown from the wheel and tend to strike the first face 32 of the support plate 31 and ricochet, or bounce back, toward the wheel. This action is often referred to as “chip whip”. The ricocheting chips may strike, or hit, the face of the wheel 12 that is adjacent to the first face 32 of the support plate 31 and may damage or mar the wheel face surface. Typical damage from whip chip may include, for example, scratching painted wheel surfaces, blemishing or scuffing finished wheel surfaces, or generally nicking or marring the wheel surface. Thus, it would be desirable to provide a wheel chuck assembly that would reduce the possible damage caused by whip chip.